Whole numbers are the set of non-negative integers: 0, 1, 2, 3, ...
Whole numbers (W) include zero and all natural numbers. Unlike natural numbers, whole numbers always include 0. They are used for counting objects that may be zero ("I have 0 apples"). Whole numbers are closed under addition and multiplication but not under subtraction or division. They form a subset of integers and are used in elementary arithmetic and everyday counting.
The concept of whole numbers developed alongside natural numbers, with zero being added later. The inclusion of zero in the number system originated in India around the 5th century CE. Zero was essential for the development of place-value notation and later calculus.